upgrade xp-home to xp-pro

Dear all,
i am working as system admin, i have cliend pcs all win-home
edition, but i want win-xp professional because i want to
connect a remote desktop connection to pcs, win-home is no that
type of option, how i will change xp-home to xp-pro without
formating, can i do like (upgrade - win2000 to xp)upgrade option
or not, if i want upgrade withoout formating and without data
loss, pls give me good suzzestions for this,
or
i want remoteadmin software with i can use in win home also

i think u can't update ur xp-home to xp professional coz both of them are
same platform u know...but one thing u can do ...u can install windowsxp in
other drives (leaving the drive which u have previously loaded xp-home)..for
doing this not even a single file is deleted which u have saved it
previously on ur xp-home..good luck..need further assistance reply here.....

Note: when u choose other drive for os installation make it for ntfs..then
only u can install it properly..here don't go for FAT32

You will need to get an XP-Home to XP-Pro upgrade for each of the units
you want to upgrade. Believe it or not, Microsoft thought that one
through when they created the XP-Home version . . . and there is a charge
for the upgrade. ;-)

I think there is also an upgrade from Win2K to XP-Pro but I am not sure (I
skipped Win2K altogether).